I think at minimum it allows people who match between sets of characteristics, and so if you happen to resonate or match with your astrological sign - and someone else does - and you've both read and know the stereotypical or associated traits, then to some degree you may better know what kind of person you're getting involved with; obviously there's a selection bias that people aren't "into" or match with their sign's defined traits won't believe in it, and so they'll filter themselves out of this filtering system.
